ON CTENOPLLANA. 341 
(13) The testes of Ctenoplana are enclosed within a tunica 
propria. 
(14) The pinnate seizing tentacles (Greiftentakel) of Cteno- 
plana and Ctenophora, retractile within definite sheaths, belong 
to the same category of structures to which the proboscis of 
Nemertines and certain Rhabdoccele Planarians belong. 
(15) Creation of a new order, the Archiplanoidea, for the 
reception of Cceloplana and Ctenoplana. The order will thus 
contain two families, the Celoplanide and the Cteno- 
planide. 
(16) Hypothesis of the diphyletic origin of Bilateralia. 
In conclusion, as I am about to leave Sydney, I wish to 
repeat my thanks to Professor W. A. Haswell for his kindness 
and hospitality to me. 
SypNEY; June 29th, 1896. 
EXPLANATION OF PLATE 21, 
Illustrating Mr. Arthur Willey’s paper “‘ On Ctenoplana.” 
N.B.—My material was preserved in sublimate and in a sublimate-acetic 
mixture, and stained with alum-cochineal. 
Fic. 1.—Ctenoplana rosacea, n. sp., from dorsal aspect. The two 
pinnate tentacles are extended, the ctenophoral plates alternate with the 
gastric lobes, the two middle large gastric lobes mark the stomachal plane ; 
in the dorsal centrum is seen the otolith, surrounded by an incomplete circlet 
of ciliated sensory tentacles paired about the tentacle axis; the spots round 
the margin of the skirt represent crimson pigment spots. From living speci- 
men. N.B.—The crosses indicate the positions of the male genital organs. 
Fie. 2.—C. rosacea. In swimming attitude. From living specimen. 
Tentacles retracted. ¢.0. Opening of tentacle sheath. 
Fic. 8.—C. Korotneffi, n. sp. In swimming attitude. The space indi. 
cated by dotted line below the aboral sense-organ was dimly seen through 
the body, and probably represents the space into which the sense-organ is 
withdrawn on retraction, although it might represent the funnel vessel. 
VOL. 39, PART 3,—NEW SER. Z 
